Factors determining the distribution of introduced mammals in nature reserves of the southern province, New Caledonia

Abstract

We studied the distribution of introduced mammals in six nature reserves of New Caledonia's southern province. Polynesian rats (Rattus exulans) were common in both rainforest and shrubland but their abundance decreased with increasing altitude. Ship rats (Rattus rattus) were abundant in rainforest but less numerous in shrubland and their abundance did not increase with altitude. We found no Norway rats (Rattus norvegicus) or house mice (Mus musculus domesticus) in reserves. Feral pigs (Sus scrofa) used mainly rainforest but also shrubland and preferred foraging in valleys with alluvial soils. Rusa deer (Cervus timorensis) selected shrubland over rainforest. Feral cats (Felis catus) were widely distributed in the reserves, whereas dogs (Canis familiaris) strayed into reserves but did not form feral populations.